The present invention relates to a semiconductor device and a manufacturing technique for the same. Particularly, the present invention is concerned with a technique effective in its application to a semiconductor device having a package structure wherein a semiconductor chip disposed on a substrate is sealed with a resin seal member.
As to semiconductor devices built into small-sized electronic devices such as portable telephones, portable information processing terminal devices and personal computers, there exists a demand for the reduction of thickness and size and an increase in the number of pins. As a semiconductor device suitable for satisfying such a demand there is known, for example, a semiconductor device called BGA (Ball Grid Array) type. As to the BGA type, various structures have been proposed and manufactured as products. Among them, BGA type of a face-up structure is most popular which permits the use of existing manufacturing equipment and which can be manufactured at low cost.
A BGA type semiconductor device of a face-up structure mainly comprises a wiring substrate, a semiconductor chip disposed on one main surface of the wiring substrate, plural bonding wires for bonding between plural connections formed on a main surface of the semiconductor chip and plural connections formed on the main surface of the wiring substrate, a resin seal member for sealing the semiconductor chip and the plural bonding wires, and plural ball bumps serving as terminals for external connection and disposed on another main surface (back side) opposite to the one main surface of the wiring substrate.
In the manufacture of a BGA type semiconductor device having a face-up structure there is used, for the improvement of productivity, a multiple wiring substrate having plural substrate forming areas (product forming areas) which are arranged in one direction continuously at predetermined intervals. A resin seal member forming area is provided in each substrate forming area of the multiple wiring substrate and a chip mounting area is provided in each resin seal member forming area. Each substrate forming area is surrounded with a separating area. By cutting the separating area with a cutting tool to cut out the associated substrate forming area there is formed a wiring substrate. The operation for cutting out each substrate forming area is performed, for example, after successive execution of chip mounting, wire bonding, resin seal member forming and bump forming steps.
For forming a resin seal member for sealing a semiconductor chip there is adopted a transfer molding method which is suitable for mass production. The formation of a resin seal member by the transfer molding method is carried out using a molding die constituted mainly by upper and lower molds and with plural cavities formed in the upper mold correspondingly to substrate forming areas of a multiple wiring substrate. According to the transfer molding method, a multiple wiring substrate which has gone through a chip mounting step and a wire bonding step is positioned between the upper and lower molds of the molding die and resin is poured from pots into the cavities through culls, runners and resin pouring gates. Each cavity is mainly composed of a quadrangular main surface opposed to a main surface of a semiconductor chip and four side faces extending along the four sides, respectively, of the quadrangular main surface. The cavities are disposed on the resin seal member forming areas of the multiple wiring substrate so as to cover semiconductor chips. As the resin there is used a thermosetting epoxy resin for example.
As to the manufacture of a BGA type semiconductor device using a carrier substrate, it is described, for example, in Japanese Published Unexamined Patent Application No. Hei 10(1998)-135258.